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newLISP Fan Club

Forum => Anything else we might add? => Topic started by: Lutz on October 08, 2008, 07:43:20 AM

Title: de-structuring in newLISP
Post by: Lutz on October 08, 2008, 07:43:20 AM
Some blogger was showing de-structuring in Clojure (a Java based LISP). Just wanted to share how easy this is in newLISP using 'unify' and 'bind':


Code Select
(set 'struct '((one "two") 3 (four ("five"))))
(set 'pattern '((A B) C (D (E))))

; de-structure
(bind (unify pattern struct))

A → one
B → "two"
C → 3
D → four
E → "five"



'unify' returns an association list and 'bind' binds the associations
Title:
Post by: cormullion on October 08, 2008, 09:37:17 AM
I don't get that - what's  de-structuring for? (no entry in wikipedia...). But I like to see unify being used - I've yet to use it in my stuff!



(PS: I think Fanda is a Clojure user now...- saw his name crop up on a Clojure mailing list...)
Title:
Post by: newBert on October 08, 2008, 10:08:05 AM
Some things in CloJure can be done simply (more simply) in NewLISP



e.g.:
Code Select
;;; CloJure ;;;
; (defn my-zipmap [keys vals]
; (loop
; [map {}
; ks (seq keys)
; vs (seq vals)]
; (if (and ks vs)
; (recur (assoc map (first ks) (first vs))
; (rest ks)
; (rest vs))
; map)))
;
; (my-zipmap [:a :b :c] [1 2 3])
; => (:b 2, :c 3, :a 1)

Code Select
;;; NewLISP ;;;
(println (map list '(a b c) '(1 2 3)))
; => ((a 1) (b 2) (c 3))

... or maybe I did not undestand at all ?



P.S.:
Quote from: "cormullion"I don't get that - what's  de-structuring for?

neither do I

(//%3C/s%3E%3CURL%20url=%22http://smileys.sur-la-toile.com/repository/Cligne/b_wink.gif%22%3E%3CLINK_TEXT%20text=%22http://smileys.sur-la-toile.com/reposit%20...%20b_wink.gif%22%3Ehttp://smileys.sur-la-toile.com/repository/Cligne/b_wink.gif%3C/LINK_TEXT%3E%3C/URL%3E%3Ce%3E)
Title:
Post by: xytroxon on October 08, 2008, 02:12:18 PM
I think it's from this blog: "Some notes about Clojure"

//http://items.sjbach.com/16/some-notes-about-clojure



reddit programming: comment link. (//http)



If you understand it enough, you can taunt er. "comment" about newLISP's version at both of above links ;)



-- xytroxon
Title:
Post by: cormullion on October 09, 2008, 10:10:50 AM
Quote from: "xytroxon"If you understand it enough, you can taunt er. "comment" about newLISP's version at both of above links ;)


;) always tempting! But then I liked what Rich Hickey (Mr Clojure) said in a comment on another blog somewhere - if you want others to respect your language, then respect their's too...



I like design of the clojure web site (clojure.org) as well. (Lutz - perhaps it's time to retire all those HTML CENTER tags on newlisp.org?)
Title:
Post by: newBert on October 09, 2008, 10:53:37 AM
Thanks for the links, I understand a little better now what it is about ...



... and I find Lutz's example (in NewLISP) clearer and more readable (and more "Lispic") than those in CloJure.



CloJure
Code Select
(def flat "flat")
(def tree '(("one" ("two")) "three" ((("four")))))
 
;; Simple binding (like Common Lisp's LET*).
(let [var1 flat
      var2 tree]
  (list var1 var2))
 
-> ("flat" (("one" ("two")) "three" ((("four")))))
 
;; Full destructuring.
(let [var1 flat
      [[a [b]] c [[[d]]]] tree]
  (list var1 a b c d))
 
-> ("flat" "one" "two" "three" "four")

NewLISP
Code Select
(set 'flatten "flat")
(set 'tree '(("one" ("two")) "three" ((("four")))))

;; Simple binding (like Common Lisp's LET*)
(let (var1 flatten
var2 tree)
(list var1 var2))

;-> ("flat" ("one" ("two")) "three" ((("four"))))

;; Full destructuring.
(let (var1 flatten)
  (bind (unify '((A (B)) C (((D)))) tree))
  (list var1 A B C D))

;-> ("flat" "one" "two" "three" "four")
N.B.:(flat (list flatten tree)) seems simpler for full destructuring ;-)



That gave rise to play with unify and above all to understand it.

(And I did not finish understanding yet)

;-)
Title:
Post by: xytroxon on October 09, 2008, 11:03:03 AM
Quote from: "cormullion"
Quote from: "xytroxon"If you understand it enough, you can taunt er. "comment" about newLISP's version at both of above links ;)


;) always tempting! But then I liked what Rich Hickey (Mr Clojure) said in a comment on another blog somewhere - if you want others to respect your language, then respect their's too...


That's why I said you need to understand it first!



Clojure has a lot of "Why did they want or have to do it that way?" changes.



Differences with other Lisps:

//http://clojure.org/lisps



So it is interesting to study... But hard to challenge the language without a lot more experience using Clojure.


Quote from: "cormullion"
I like design of the clojure web site (clojure.org) as well. (Lutz - perhaps it's time to retire all those HTML CENTER tags on newlisp.org?)


For looking like it doesn't need to use javascript, it has too much javascript for my taste ;)



-- xytroxon
Title:
Post by: newBert on October 09, 2008, 11:04:18 AM
Quote from: "cormullion"
;) always tempting! But then I liked what Rich Hickey (Mr Clojure) said in a comment on another blog somewhere - if you want others to respect your language, then respect their's too...


Comparing can be also a token of respect, because of the interest that we take to learn and understand another language ... :-)
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